Though HIV is traditionally considered a risk for injection drug users, in recent years infections in this demographic group have declined from a peak of 35,000 infections in the 1980s to just around 3000 in 2013. The tremendous decline can be attributed to better testing coupled to wider availability of clean needles via pharmacies or formal needle-exchanges. That 37% of injection drug users infected with HIV are unaware of their diagnosis (vs. just 14% in the whole HIV positive population) is a major factor that can facilitate the explosive spread of this virus as has happened in Indiana.

However, the uptake and availability of these services is not uniform and some users failing to avail themselves of these preventative measures. Indiana is one such state where needle-exchanges are unable to operate legally. Consequently, as part of the public health emergency, Governor Pence has allowed the operation of these vital resources in Scott County as an emergency measure. (Thankfully, in Pittsburgh we have a robust needle exchange, Prevention Point Pittsburgh, on whose board I serve).

The lesson to be drawn from Indiana's experience is that infectious diseases can exploit complacency and imperfect defenses. This illustrates that when it comes to infectious diseases all defenses--including needle exchanges for those infections spread via injection drug use--most be in continual operation.